The applicant's long-term career goals are to characterize the development of complex auditory processing, to disseminate that knowledge to the lay and academic public, and to evaluate similar processing in infants at-risk for hearing impairments. In the short-term, the applicant intends to set- up the facilities needed for infant psychoacoustics procedures, to carry- out the proposed research, and to establish contact with local individuals involved in related research and service fields. The RCDA will provide the applicant time to develop contacts with the broader scientific community, a necessary condition for development of a productive and innovative research career. The award will also provide time for the infant laboratories to be set-up and necessary procedures to be developed. Some of these procedures will be difficult to implement and will require a major time commitment, which only the RCDA can provide. Finally, the RCDA will allow for the initiation of collaborative research. A wealth of scientists interested in areas related to the applicant's research reside in the institution. In addition, collaborative projects are being discussed both with individuals within the applicant organization and at neighboring facilities. The institution will release the applicant from all teaching, except for periodic courses related to the proposed research program, and administrative responsibilities will be reduced to the minimum required to maintain connections with her affiliated programs. The proposed research will investigate the development of infants' auditory spatial perception in localization and lateralization tasks and will delineate the acoustic features that underlie those abilities. Localization in the sound-field will be tested to assess performance in a natural environment, while earphone studies will permit isolation of the binaural cues likely to be used in the field. Across studies, the amount of interaural timing information provided by sounds will be varied to see how and in what way additional cues aid infants' spatial perception.